Which of the following is a micronutrient

Options

A. Ca
B. Mg
C. K
D. Ni

Answer

To determine which of the given options is a micronutrient, we need to understand the classification of essential elements in plants based on their quantitative requirements.

### Step-by-Step Solution:

1. **Understand Nutrient Classification**: Nutrients are classified into two main categories: macronutrients and micronutrients.
- **Macronutrients** are required in larger amounts (greater than 10 mmol/kg of dry matter).
- **Micronutrients** are required in smaller amounts (less than 10 mmol/kg of dry matter).

2. **Identify Macronutrients**: Examples of macronutrients include:
- Carbon (C)
- Hydrogen (H)
- Oxygen (O)
- Nitrogen (N)
- Phosphorus (P)
- Sulfur (S)
- Potassium (K)
- Calcium (Ca)
- Magnesium (Mg)

3. **Identify Micronutrients**: Examples of micronutrients include:
- Iron (Fe)
- Manganese (Mn)
- Copper (Cu)
- Molybdenum (Mo)
- Zinc (Zn)
- Boron (B)
- Chlorine (Cl)
- Nickel (Ni)

4. **Analyze the Options**: The options provided are:
1. Calcium (Ca) - Macronutrient
2. Magnesium (Mg) - Macronutrient
3. Potassium (K) - Macronutrient
4. Nickel (Ni) - Micronutrient

5. **Select the Micronutrient**: From the analysis, Nickel (Ni) is identified as a micronutrient, while the other options (Calcium, Magnesium, and Potassium) are macronutrients.

### Conclusion:
The correct answer is **Nickel (Ni)**, as it is the only micronutrient among the options provided.

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